Earth boring tool



Sept. 1, 1942.

C. E. REED EARTH BORING TOOL Filed Feb. 26, 1940 4 Sheets-Sheet l Sept. 1, 1942. c. E. REED 2,294,629

EARTH BORING TOOL Filed Feb. 26, 1940 4 Sheets-Sheet 2 flare/26913? JZeed M Sept 1,1942. 4 (1E. REED 2,294,629

EARTH BORING TOOL Filed Feb. 26, 1940 4 Sheets-Sheet 3 Sept. 1, 1942. c. E. REED EARTH BORING TOOL Filed Feb. 26, 1940 4 Sheets-Sheet 4 Gum/MA;

memes Sept. 1, 1942 EARTH BORING TOOL Clarence E. Reed, Wichita, Kans., assignor to Chicago Pneumatic Tool Company, New York, N. 1., a corporation of New Jersey Application February 26, 1940, Serial No. 320,955

9 Claims. (01. 255-71) a bit head. Some of these cutters, and particularly those cutters at the side of the bit head for disintegrating the area at the side of the hole, are rotatable about axes which are inclined to the horizontal.

Cutters which rotate about such inclined axes have imposed upon them operating forces which tend to twist the cutter upon its spindle in such manner that the axis of the cutter and the axis of the spindle are not in alignment. The consequent disalignment impairs the cutting efficiency of the cutter and causes destructive wear upon the cutter bearings'and upon the cutter teeth. An important feature of the present invention is the provision of means which will tend to maintain'the axis of the cutter in alignment with the axis of the spindle.

Other features of the invention will be apparent from the following description.

In the drawings: 1

Figure 1 is a plan view of the underside of an earth boring tool embodying the invention.

Fig. 2 is a section on the line 2-2 of Fig. 1, only the cutters in the sectional plane being shown.

Fig. 3 is a side elevation of the hanger appearing in Fig. 2. I

Fig. 4 is a side elevation of the removable spindle portion of Fig. 2.

Fig. 5 is a section on the line 5-5 of Fig. 1.

Fig. 6 is a section on the line 6-6 of Fig. 1.

Fig. 7 is an elevation of the removable spindle portion of Fig. 5.

Fig. 7a. is a fragmental section through the cutter of Fig. 5.

Fig. 8 is an elevation of the bridge member appearing at the righthand end of the spindle of Fig. 2.

Fig. 9 is a section of .a modified arrangement of the assembly appearing in- Fig. 2.

Fig. 10 is a side elevation of the hanger of Fig. 9.

Fig. 11 is a side elevation of the removable spindle portion of Fig. 9.

Referring first to the embodiment of the invention appearing in Figs. 1 to 8, inclusive, this earth boring tool includes the side cutters I, 2, and 3 and the central cutter l. The side cutters I, 2, and 3 are rotatable about axes which lie in planes which pass through the axis :c-a: of the bit head 5, and which are 120' apart. The centhe plane containing the axis of rotation of the side cutter I. All. of the axes-of rotation of the side cutters are inclined, so that they converge downwardly and inwardly of the drill toward the bit head axis. It is preferable that the axis of rotation of the center cutter 4 also incline downwardly and inwardly of the drill.. The teeth which are formed upon the exteriors of these several cutters preferably are of the formation disclosed in Reed Reissue Patent No. 15,126, dated June 14, 1921.

The side cutter l is preferably of frusto-conical shape, the larger diameter of this cutter being disposed outwardly of the bit head. This cutter disintegrates an annular area at the side of the hole which includes clearance for the bit head,

and this area preferably inclines downwardly and inwardly toward the center of the hole. The cutter is exteriorly formed with teeth in extending throughout the axial length of the cutter.

The central cutter a is preferably of frusto-' conical formation, and in the relationship shown, it disintegrates a circular area at the center of the hole which is horizontal, or perpendicular to the drill axis. As appears from Fig. 2, the area disintegrated by the central cutter a will be higher than the inner part of the area disintegrated by the side cutter I. Annular grooves 41) may be formed in the exterior of the cutter 4, so that the teeth lengthwise of the cutter are notched.

To support the side cutter l and the central cutter 4 from the drill head 5, a hanger 6 and a removable spindle member I are provided. The hanger 6 is of the formation disclosed and.- claimed in Reed Patent No. 2,058,625, dated 0ctober 27, 1936. It includes a shank 8 which may be affixed to the side of the bit head, and a spindle 9 projecting laterally from the lower end thereof. Through the spindle 9 is formed a bore hole to receive the stem ID of the removable spindle member 1. The spindle member I also includes a flange I! having a face I! which bears against the free end face of the spindle 9, and includes a spindle l3 which projects from the side face of the flange H which is opposite from the stem 10.

To rotatably mount the cutter l, the spindle 9 at its base has formed therein a groove M to constitute a raceway for frusto-conical, antifriction roller bearings l5. Thebottom of the groove I 4 is of conical formation converging toward the free end of the spindle 9. At its free end, the spindle 9 is formed with an exterior cylindrical surface l6 upon which roll the cylintral cutter 4 rotates about an axis which lies in drical anti-friction roller bearings 11. The roller eral surface ll of the flange bearings I! are prevented from movement toward the free end of spindle I by the surface II of the flange H which overlies the ends of the rollers. At its outer periphery the flange II is formed with a cylindrical surface It.

Cutter l. is formed internally with conical shaped surface 20 which bears upon the roller bearings II. This cutter also includes a counterbored cylindrical surface 2| which constitutes a raceway for the roller bearings 11. At its innermost end the cutter is formed with a further enlarged eounterbore providing a cylindrical surface 22 which bears frictionally upon the periph- The shoulder 23. which is presented between the counterbore surfaces 2| and 22, bears frictionally against surface l2 of the flange Adjacent the hanger 4 the cutter I is provided with a surface 24 which frictionally bears against the inner face of the hanger. I

To assemble the cutter I, the roller bearings II are flrst placed in position in the raceway H.

The cutter is then passed over the free end of the spindle 9 so as to bring the surface 20 thereof upon the roller bearings l5. Roller bearings II are then inserted in place between the surface It or the spindle and the internal surface 2| of the cutter. The removable spindle member 1 is then placed in position by inserting its stem It in the bore through the spindle 5, and welding 23 is applied at its end to hold the removable spindle member in place. The cutter is positively retained in place upon the spindle 9 by the abutting surfaces l2 and 23. In order that the roller bearings II will not sustain any inward end thrust of the cutter, they should be of less axial length than the raceway surface 2|. Outward end thrust of the cutter is sustained by the surface 24 of the cutter.

The central cutter 4, in accordance with the invention, frictionally bears upon the exterior of the projecting spindle l3 of the removable spindle member I. In order to reduce the wear upon the spindle and cutter, it is desirable that the spindle bearing surface and that the internal bearing surface of the cutter be hardened by any hard-facing material, as is indicated at 25 and 26, respectively. The clearance of the running flt of the center cutter on its spindle should be about .010 inch. To retain the cutter 4 upon its spindle I3, a bridge member 21 may be aflixed, as by welding, upon the reduced end portion 28 of the spindle. This bridge member 21 overlies the end of the cutter 4, so that the cutter frictionally bears against it.

The cutter 2 is provided exteriorly at the base part thereof with teeth 2a which are of generally frusto-conical formation, and is provided at the inner part thereof with teeth 2c separated from the teeth 2a by a deep, wide groove 2b. The teeth 2a are of the same diameter as the teeth la at the larger end of cutter I, and these teeth 2a act upon the same inclined area as that disintegrated by the teeth la, but since the teeth 2:; are not aslong as teeth la, only the outer portion of this area is disintegrated by them. The teeth 20 cut an annular area which is next inwardly from the inner extremity of the annular area out by the teeth la. These teeth 2c are at a sharp angle with respect to the cutter, so that the area cut thereby inclines upwardly toward the outer extremity of the area cut by the central cutter 4. However, the area which is cut by the teeth 20 does not extend inwardly to the area cut by the teeth of cutter 4, an annular 7 area existing between them.

To rotatabiy support the cutter 2, a hanger 33 having a removable portion 3| is provided. The hanger is formed with a shank 32 by which it may be amxed to the side of the bit head 5, and is formed with a spindle 33 having a bore therethrough to receive the stem 34 of the removable portion 3|. The spindle 33 has formed therein, at the base portion thereof, a groove 35 constituting a raceway to receive frusto-conical anti-friction roller bearings 36. The bottom of this raceway 35 converges toward the free end of the spindle. Toward the free end of the spindle 33 is formed a second groove 31, the bottom of which is a cylindrical surface, to receive cylindrical anti-friction roller bearings 33. The extreme end of the spindle is formed with a cylindrical exterior surface 33.

The interior of the cutter 2 is formed with a frusto-conical surface 40 at the base portion thereof to bear upon the roller bearings 35, and is formed centrally of the length of the cutter with a cylindrical surface 4| to bear upon the antifriction rollers 38. Slightly inwardly from the small end of the cutter is formed an internal flange 42 which provides an inwardly facing surface 43, Fig. 7a, which will frictionally bear upon the exterior surface 39 of spindle 33. Immediately within the inner end of the cutter is formed a counterbore providing an internal cylindrical surface 44 and a shouldered surface 45.

The surface 44 bears frictionally upon the peripheral surface 46 of the flange 41 of the removable portion 3|. Surface 45 bears against the inner surfaces 48 of flange 41, these surfaces being perpendicular to the axis of the cutter.

In order to assemble the cutter 2, the roller bearings 36 and 38 are first placed in their respective raceways 35 and 31. The cutter 2 is then passed over and upon them, this alsobringing intemai surface 43 of the cutter upon the surface 39 of spindle 33. The stem 34 of the re-, movable portion 3| isthen inserted in the bore of the spindle 33 and is afllxed in place by welding. when so assembled, the cutter 2 will be prevented from displacement oif of its spindle by reason of thefrictional end bearing surfaces at 45 and 43. Inward end thrusts of cutter 2 are sustained by these surfaces 45 and 48, while outward end thrusts of-the' cutter are sustained by the end face 49 of the cutter bearing against the hanger 30.

g The cutter 3 is formed at its base portion with teeth 3aand at its smaller end with teeth 30 separated by a groove 3b from teeth 3a. The teeth 3a are of the same diameter as the teeth la and 2a, and act upon the same area on the bottom of the bore hole which is cut by the teeth la and 21:. Teeth 3a, however, are slightly longer than the teeth 2a, although not as long as teeth la, so that the area cut bythe teeth 2a is extended further inwardly to the center of the drill hole by the teeth 3a. Teeth 3c cut the area at the bottom of the bore hole just outside of the area cut by the teeth of cutter 4, and extending up to the inner edge of the area cut by the teeth 2a. This is the area left uncut between teeth 2a and cutter 4. This area cut by the teeth 30 is an inward and upward continuation of the inclined area cut by the teeth 20 inasmuch as these two areas lie upon the same generally conical surface between the inner edge of the area cut by teeth la, and the outer edge of the area cut by the teeth of cutter 4.

The support for the cutter 3 is identical with the support for the cutter 2, so that a hanger and removable portion fabricated for .the cutter 2 will serve for the cutter 3. In this respect, the

providing a raceway for the frusto-conical roller bearings 52, and providing a raceway for the cylindrical roller bearings 63. The interior of the cutter 3 is formed with a flange 64 which friction- I having a cylindrical bottom surface to constitute a-raceway for cylindrical anti-friction roller bearlugs 61. v The removable spindle member 63 is provided hanger 66 for the cutter 3 includes a spindle 6| 3 with Mg 69 which provides upon its t ri a cylindrical surface III of large diameter and a cylindrical surface H of smaller diameter located nearer the stem 64. An annular recess i2 is formed in the side face 13 of flange 63 adjacent ally bears upon the free end of the spindle ll. the stem 64 to receive the free end of'the spindle The removable portion 56 is formed with a flange 56, against which the cutter frictionally bears, corresponding to the identically shaped surfaces for cutter 2. It will be understood that the in- 66. The surface 'll serves as a raceway for cylindrical anti-friction bearings 16.

Internally of cutter 60 are formed a cylindrical surface 16 to bear upon bearings 61, and a cylintemal bearing surfaces of the cutter 3 are shaped dri al' rt 11, h inner portion of t identically with the internal bearing surfaces of the cutter 2, the only difference between these cutters residing in the formation of and location of the particular cutter teeth upon their exteriors.

The cutters I, 2, 3, and 4 may be assembled upon their spindles while the hangers 6, 30, and so are apart from the bit head. Before these hangers are affixed to the bit head, the flushing face 'l'l. bears upon the bearings 14 and the outer portion of surface 11 bears frictionally upon the I peripheral surface-10 of flange 6301 the removable spindle member 63. The shoulder surface 29 18 formed within the cutter, between surfaces 16 and TI bears, upon the face 13 of flange 69, and this serves to retain the cutter against inward axial movement. The surface I9 upon the cutter fluid distributing member 51 should be afllxed in t r b hearing against th hanger 62.

the hole at the bottom of the bit head. The hangers and 56 with their cutters 2 and 3 should then be aflixed to the bit head. Thereafter, the assembly, including cutters l and l,

To assemble the cutter 60, the bearings 61 are first placed upon the raceway 66 and the cutter is then placed in position by passage over the free end of the spindle 65. Then the removable spinshou d be P c in P t y afl ng hange 5 30 dle member 63 with rollers id in place upon surto the bit head. When the assembly is complete,

' the end faces of the bridge member 21 will bear against the inner faces of the removable portions 3| and 55. The connection so established between the inner ends of the three cutter supports 5 will serve to strengthen them by the mutual support they receive from each other. This feature is disclosed and claimed in Reed application Serial No. 312,147,, filed on January 2, 1940.

face (I is placed in position by inserting the stem 64 through the .bore hole of the spindle 65, this The i terna bearing arrangement for the 81116 4.0 bearing surface of cutter 6i may have hardening cutters I, 2, and 3 is of importance and constitutes a feature of the present invention because the frictional and anti-frictional bearings serve to sustain the forces imposed upon the cutter'when in use. posed on a cutter positioned as shown, its spindle axis being inclined to the horizontal on the order of 30, the bottom of the cutter tends to move outwardly from the drill axis, and the upper part When the operating load is immaterial applied to them to reduce wear.

In the several embodiments of the invention which are illustrated, the side cutters are rotatable about axes which incline downwardly and inwardly of the drill. The feature of providing bearings for these cutters which will resist the tendency of the cutters to twist out of axial alignment with their spindles may be applied as well to the cutters of core bits in which type of of the cu ter e d o move n y toward the drill the cutters rotate about axes whichincline drill axis, and the cutter accordingly tends to move out of axial alignment with its spindle axis. This tendency of the cutter to move out of axial alignment with the spindle. is resisted by the cylindrical roller bearings at the inner end of the cutter which increase the free rolling of the cutter. The large frictional bearing surfaces at the inner end of the cutter also assist in overcoming the tendency of the cutter to twist upon its spintherefore tends to maintain the cutter axis coincident with the spindle axis and less wear upon the bearings and improved cutting results.

This feature of the invention of providing bearcise arrangements illustrated, both as to the posi-' tioning of the cutters and as to the bearings of the cutters. For example, although the center cutter 4 is shown with its axis of rotation in the dle- The beari arr m 1. the invention same vertical plane as the axis of its associated side cutter I, it may also be positioned in the assembly with its axis oilset slightly from a vertical plane through the bit axis. Such positioning of. the center cutter axis is desirable in some forings for si e cutters which will maintain axial mation's in which more than the usual amount of alignment of the cutters on their spindles is also 7 'movable spindle member 63 are provided, this member having a stem 64 which enters a bore hole through the spindle 65 of the hanger. Into scraping of the cutter teeth edges is required for fast cutting. This offset positioning of the cen-1 ter cutter is illustrated and claimed in my copending application Ser. No. 371,446 filed on Dec.

I claim: I

1. An annular side cutter assembly for an earth boring drill comprising a rotary cutter having ,two cutting zones inclined to each other, asupport havthe exterior of spindle 66 is formed a groove 66 .75 log projecting laterally and downwardly therefrom a spindle for rotatably mounting the cutter, a row-of-anti-friction roller bearings between the cutter and the spindle at the end of the cutter to be disposed outwardly of the drill. intersecting pairs of'friction bearing surfaces between the'cutter and the spindle at the inner end of the cutter bore, and a row of cylindrical roller bearings between the cutter and the spindle and located within the cutter between said anti-friction roller bearings and said friction bearing surfaces, said spindle including a removable portion having a flange and said cutter having an internal flange which frictionally bears against said spindle flange to afford one pair of said intersecting friction bearing surfaces and take end thrusts of the cutter inwardly of the drill.

2. In an earth boring drill, three side cutters I an earth boring drill, a roller cutter having a bore extending through said cutter and mounted on a spindle, the axis of which inclines to the axis of the drill, anti-friction roller bearings between said cutter and spindle at the high end of said inclined spindle and at the lower end portion of said spindle a cylindrical roller bearing of larger diameter than said anti-friction roller bearing, and end thrust frictional bearing surfaces on the cutter and the spindle.

4. A- side cutter assembly for an earth boring drill comprising a rotary cutter, a spindle for rotatably mounting the cutter, a row of antifriction roller bearings between the cutter and the spindle at the end of the cutter to, be disposed outwardly of the drill, a cylindrical friction bearing between the cutter and the spindle at the other end of the cutter, a rowoi cylindrical roller bearings between the cutter and the spindle and located within the cutter between i said anti-friction roller bearings and said friction bearing, and a frictional end thrust bearing between the cutter and spindle disposed between said row of anti-friction roller bearings and the row of cylindrical roller bearings.

5. An earth boring drill comprising two side roller cutter assemblies, each assembly including a side roller cutter having a bore extending through the cutter and having two cutting zones inclined to each other, a support having projecting laterally and downwardly therefrom aspindie, a row of tapered roller bearings and a row of cylindrical roller bearings between said cutter and spindle, and intersecting complementary frictional bearing surfaces at one end of the cutter and spindle securing said cutter and roller bearings on said spindle; amember connecting the inner ends of said assemblies, and one other cutter assembly comprising two cutters, one being a side cutter and the other a center cutter, a spindle therefor and a drill head connected to said last mentioned spindle and said supports and supporting said assemblies. v Y

6. In an earth boring drill three side cutters of uniform diameter, of diflerent axial lengths of cutting surface and one of said cutters recessed at its inner face, .another cutter projecting within said recess, said another cutter being mounted uporf a spindle and extending to approximately the longitudlnal axis of the drill, rolling radial bearings and rolling end thrust bearings between the said side cutters and spindles therefor, and hard faced frictional bearing surfaces on said another cutter and the spindle therefor.

7. In an earth boring drill, a side rotary cutter and spindle positioned with their axes inclined to the axis of the. drill, said rotary cutter having two cutting zones inclined to each other, antifriction roller bearings between said cutter and spindle at the high end of said inclined spindle and at the lower portion of said spindle a larger diameter bearingv than the previously recited bearings taking lateral thrusts of said cutter, interengaging end thrust bearing surfaces on said cutter and spindle, and another spindle portion inwardly from said larger diameter bearing having a hardened face periphery, and a cutter on said spindle portion.

8. In an earth boring drill, a side rotary cutter and spindle positioned with their axes inclined to the axis of the drill, said rotary cutter having two cutting zones inclined to each other, anti-friction roller bearings between said cutter and spindle at the high end of said inclined spindle and at the lower portion of said spindle a larger diameter bearing than the previously recited bearings taking lateral thrusts of said cutter, lnterengaging end thrust bearing surfaces on said cutter and spindle, and another spindle portion inwardly from said larger diameter bearing having a hardened face periphery, and a cutter on said spindle portion, said larger diameter bearing additionally comprising cylindrical roller bearings and frictional bearing surfaces.

9. An earth boringdrill comprising three cutters, each having substantially the same amount of total cutting edges 'annularly arranged, roller radial bearings and rolling end thrustbearings for said cutters, spindles for said cutters and frictional abutting surfaces retaining said cutters on said roller bearings and said spindles, and another cutter between one of said three cutters and the drill axis positioned under overhanging portions of said three cutters, the spindle for said another cutter and the bore of said cutter being hard faced, said cutters disintegrating the entire area of the bottom of the hole and including clearance at the side of the drill.

CLARENCE E. REED. 

